MONDAY, March 5, 2018 (HealthDay News) -- The longer people are obese, the greater their chances of developing heart disease, a new study suggests.

The researchers analyzed data from more than 9,000 American adults who had started participating in a study when they were in their early 60s.

That study included periodic assessments of their body mass index (BMI), an estimate of body fat based on weight and height. It also included checks for heart disease and blood levels of the protein troponin, a marker of "silent" heart damage.

The participants also provided information on their weight since age 25, which gave a long-term overview of their weight.

The study found that those with a longer history of being overweight or obese were more likely to test positive for troponin.

The findings suggest that maintaining a healthy weight throughout life is important for heart health as people age, the researchers said.

"We're finding that people's weight from age 25 onwards is linked to the risk of more or less heart damage, as measured by levels of the protein troponin, later in life," said study lead author Dr. Chiadi Ndumele. He's an assistant professor of medicine at Johns Hopkins School of Medicine in Baltimore.

This "underscores the likely importance of long-term weight control for reducing heart disease risk," Ndumele said in a university news release.

"What our findings suggest is that even in the absence of such heart disease risk factors as high blood pressure, diabetes or kidney disease, the number of years spent obese or overweight contributes to the higher likelihood of heart damage," he said.

More than a third of American adults are obese, and 70 percent are either overweight or obese, according to the U.S. Centers for Disease Control and Prevention.

Results of the study were published recently in the journal Clinical Chemistry.